(1) Field of the Invention
This invention is directed to the field of line-tension determination. More particularly, the invention is directed to a self-contained device that automatically determines traveling wave times that can be correlated to line tension for particular span lengths at certain temperatures.
(2) Description of Related Art
In the context of this disclosure, power lines, telephone lines or other tensioned lines or cables or ropes, etc., will be referred to as “lines,” without loss of generality. The process of determining the tension of sagging lines, particularly in the industrial arts, is routinely determined by using return wave timing in conjunction with sag-tension charts. Specifically, this approach requires a worker to impact a strung line near the attachment point to generate a traveling wave that will reflect back and forth between two supports. When the line is struck, a stopwatch is started and the elapsed time is recorded once the wave passes the number of times specified on the sag-tension chart. The resulting time is then compared against the sag-tension chart. The sag-tension chart correlates the designed tension for the type of line to the desired temperatures and designed span lengths to yield a resulting sag and tension. This tension is then compared against an engineered value provided by the engineer and the line is either tightened or slacked until the time recorded closely matches the corresponding time in the sag-tension chart. This method usually takes multiple people and the results are subject to inaccuracies due to obvious operator error.
Given that this is the standard used in the industry for the last hundred years (specifically, power lines), more modern methods and systems are desired that eliminate human error and increase efficiency without vastly changing the commonly practiced method of using the wave-return method to accurately determine line sag and/or tension. Details of such new method(s) and system(s) are provided in the following description.